Better comment inserting tests and fix implementation

rc/filetype/elixir.kak

@@ -95,7 +95,7 @@ define-command -hidden elixir-trim-indent %{
 define-command -hidden elixir-insert-on-new-line %[
     evaluate-commands -no-hooks -draft -itersel %[
         # copy '#' comment prefix and following white spaces
-        try %{ exec -draft k <a-x> s ^\h*#\h* <ret> y jgh P }
+        try %{ exec -draft k <a-x> s ^\h*\K#\h* <ret> y jgi P }
         # wisely add end structure
         evaluate-commands -save-regs x %[
             try %{ execute-keys -draft k <a-x> s ^ \h + <ret> \" x y } catch %{ reg x '' }

test/indent/elixir/insert-comment-hash/cmd

@@ -1 +1 @@
-c<ret>
+c<ret><esc><a-o>jo# comment3<ret>comment4<esc><a-o>jo#    indented<ret>indented2

test/indent/elixir/insert-comment-hash/out

@@ -1,2 +1,8 @@
 # Comment
 # comment2
+
+# comment3
+# comment4
+
+#    indented
+#    indented2